Silencer



H. P. MAXIM July .19, 1927.

SILENCER Filed Oct. 1, 1926 1 0 k nvvENroR WW 7% v ATTORNEY Patented July 19, 192 7.

.UNITED STATES PATENT OFFICE.

HIRAM PERCY MAXIM, O]? HARTFORD, CONNECTICUT, ASSIGNOR TO THE MAXIM SILENCER COMPANY, OF HARTFORD, NECTICUT.

SILENCER.

CONNECTICUT, A CORPORATION OF CON- HEISSUED Original application filed March 23, 1922, Serial No. 546,126. Divided and this application filed October '1, 1926. Serial No. 138,996.

The present invention relates to silencers or mufll'erssuch as are used in connection with gas or oil engines to reduce the noise of the exhaust or in connection with various kinds of steam and pneumatic machinery for deadening the discharge or intake noises thereof.

The invention is particlularly directed to improvements in the'type of silencers de- 10 scribed generally inmy pending application Serial No. 546,126, filed March 23, 1922, of which this present application is a division.

One object of the invention is to provide a mufiier or silencer of the general character above mentioned which will effectively per form its functions without creating back pressure.

To this end, the invention contemplates broadly the provision, in an exhaust or in take silencer, of a silencing conduit constructed and arranged to obstruct the escape of the sound waves without throttling the flow of the sound propagating medium.

In carrying out this feature of this invention, the silencing conduit is made to comprise at least one section, the walls of which are shaped in accordance with the principles of Venturi tube construction to provide agradually contracting portion and a gradually expanding portion, the former being arranged to discharge into the latter. As the exhaust gases pass through a conduit constructed in this manner, the sound waves which strike the tapering walls ofthe contracting portions are reflected backwardly, and are trapped and as a result only such sound waves escape as pass directly through the small end-of the contracted portion without striking against.the converging walls thereof. By reason of the Venturi action of the expanding or diverging portion of the conduit, the velocity of the gases is increased in the restricted portion to such an extent that the volume of flow per unit of time of said gases or propagating medium is not matcriallyreduced and consequently the discharge capacity of the conduit is not reduced and no undesirable back premure is created.

Another object of the invention is to providecertain new and useful improvements in silencers tending to simplify their construction, increase their eflicie'ncy and reduce the cost of their manufacture.

With these latter objects in view, as will mutller therein illustrated comprises a cylindrical casing'consisting of a body portion 35 and a' cover plate 36 which are rigidly secured together by means of bolts 37, the latter extending through outwardly projecingears 38 on the body and cover plate. The body portion of the muffler casingis provided with a peripheral inlet spud. 39 and with an axial outlet orifice 40. The interior of the mufller casing is provided with two intertwining generally scroll-shaped ribs 41 and 42 which extend from the cover plate 36 of the cylindrical muiiler casing to the end wall of the body portion 35 and are so arranged as to afford two separate spiral or involutc passages 44 leading inwardly to the central portion of the casing and through which the incoming exhaust gases must pass in order to reach the outlet orifice 40. To facilitate the casting of the spiral ribs 41 and 42. the rib 41 is made integral with the body of the casing 35 while the rib 42 is made integral with the cover plate 36, this expedient providing for sufficient space between the ribs of each casting to insure that the ribs will draw properly from the sand of the mold,

To effect the trapping of the sound waves without retarding the flow of the sound propagating medium, each spiral passage 44 is provided with a series of Venturi sections 45 each of which is formed by means of a convexly curved lateral projection 46 upon one of the opposed spiral ribs which form the opposite side walls of the passageway. The Venturi sections 45 have substantially the same effect upon the exhaust gases and sound waves as the Venturi sections deof embodying Venturi sections in a silencing conduit of spiral form. a. considerable economy of space is effected. The particular construction described is of extremely simple and rugged construction and is inexpensive to manu'lm-ture, the mufller comprising only two castings which are bolted together.

lt will he understood that the invention may be embodied in various other forms than that shown and that many changes in the details of ccnstruction and arrangement of parts may be rcsorted to without departing from the spirit and scope of the invention as hereinafter claimed.

\Vhat I claim is:

1. A silencer comprising, a cylindrical casing having a peripheral and an axial opening therein. a silencing conduit of spiral form within said casing extending between said openings, said conduit having a succession of contracting and expanding sections distributed throughout its lengt-h to form a series of Venturi-like passageways therein.

2. A silencer comprising. a pair of castings each having an integral spiral flange extending from a side face thereof. said castings being secured together with said flanges in opposed intertwined relation, said flanges coacting, with the opposed side faces to provide two spiral silencing conduits leading outwardly from an axial chamber. and projections on said flanges cooperating with the adjacent flanges to provide a series of contracting and expanding sections of Venturi-like character in said conduit 3. A silencer comprising, a pair of castings each having an integral spiralflange -extending from a side face thereof, said castings being secured"together with said flanges 1n opposed intertwined relation, said flanges enacting with the o posed side faces to provide two spiral si encing conduits leading outwardly from an axial chamber, and projections on said flanges cooperating with the adjacent flanges to provide a series of contracting and expanding sections of Venturidike character in said conduit, one of said castings having an outer circular flangc integral therewith and coacting with said other casting to provide an annular chamber surrounding said spiral conduits. said circular flange having an opening therein for the introduction of the exhaust gases.

4. A silencer comprising. an annular cast.- ing having an integral peripheral flange and an integral spiral flange extending from a side face thereof. a disk-shaped casting hav iiig an integral spiral flange extending from a side face thereof, said castings being secured together with said spiral flanges in opposed intertwined relation, said spiral flanges coacting with the opposed side faces to provide a central chamber having an axial opening and two spiral silencing conduits leading outwardly from said chamber, said circular flange coacting with said diskshaped casting to provide anannular chamber surrounding said spiral conduits. and convex projections on said spiral flanges cooperating with the adjacent flanges to provide a series of contracting and expanding sections of Venturi-like character in said conduits.

In testimony whereof I have affixed my signature.

HIRAM PERCY MAXIM. 

